Heat energy utilization optimization system based on seawater direct electrolysis hydrogen production system

Abstract

The invention relates to a heat energy utilization optimization system based on a seawater direct electrolysis hydrogen production system. The heat energy utilization optimization system comprises a first-stage heat exchange pipeline and a second-stage heat exchange pipeline, the first-stage heat exchange pipeline comprises a first heat exchanger, a solar heating device and an electric heating device which are sequentially connected through pipelines, a third port of the first heat exchanger is connected with the output end of the hydrogen production system, and the output end of the electric heating device is connected with the input end of the hydrogen production system; the second-stage heat exchange pipeline comprises a second heat exchanger and a pressurizing pipeline, a first port and a third port of the second heat exchanger are connected with the two ends of the cooling water circulation system respectively, a fourth port of the second heat exchanger is connected with the input end of the mass transfer system, and the output end of the mass transfer system is connected with the pressurizing pipeline used for pressurizing alkali liquor in the pipeline. The heat energy utilization rate of renewable energy sources in the hydrogen production process is increased, collaboration and optimization of the system on multi-grade energy such as heat and work are achieved, and good environment friendliness is achieved.

Description

TECHNICAL FIELD

[0001] The application relates to a heat energy utilization optimization system based on a seawater direct electrolysis hydrogen production system and belongs to the hydrogen production technical field. BACKGROUND

[0002] As a core carrier for realizing deep decarbonization of energy, hydrogen energy has become a key breakthrough for reconstructing an energy system. Electrolytic hydrogen production technology, especially the technology of decomposing water into hydrogen and oxygen by using green power generated from renewable energy, is a core path for realizing large-scale production of green hydrogen. The technology of directly electrolyzing seawater to produce hydrogen is widely considered as a key direction for realizing large-scale application of green hydrogen energy in the future.

[0003] In the seawater direct electrolysis hydrogen production system, there are significant temperature differences between the subsystems, and part of the energy of the hydrogen production system is lost in the form of heat energy in the interaction process. In particular, the electrolytic tank of the hydrogen production system usually needs to be maintained at a working temperature of 70-80 DEG C, while the mass transfer system and other subsystems for direct water replenishment are at 40 DEG C or room temperature, thereby causing a large amount of heat energy to be wasted in the alkali solution circulation process. Therefore, improvement is urgently needed. SUMMARY

[0004] In order to overcome the shortcomings that in the existing seawater direct electrolysis hydrogen production system, the required temperatures of reactions of the subsystems are uneven, a large amount of heat energy is wasted in the alkali solution circulation process, and the temperature fluctuation of the electrolytic tank caused by insufficient heat coordination between the systems further affects the service life of the seawater direct electrolysis hydrogen production system, the application designs a heat energy utilization optimization system based on a seawater direct electrolysis hydrogen production system, which improves the heat energy utilization rate of renewable energy in the hydrogen production process and has good environmental friendliness.

[0005] In order to achieve the above purpose, the application adopts the following technical scheme: The heat energy utilization optimization system based on the seawater direct electrolysis hydrogen production system comprises a primary heat exchange pipeline and a secondary heat exchange pipeline. The primary heat exchange pipeline comprises a heat exchanger one, a solar heating device and an electric heating device which are connected in sequence through pipelines. The port three of the heat exchanger one is connected with an output end of the hydrogen production system. The output end of the electric heating device is connected with an input end of the hydrogen production system. The secondary heat exchange pipeline comprises a heat exchanger two and a pressurizing pipeline. The port one and the port three of the heat exchanger two are connected with two ends of a cooling water circulation system respectively. The port four of the heat exchanger two is connected with an input end of a mass transfer system. The output end of the mass transfer system is connected with the pressurizing pipeline for pressurizing the alkali solution in the pipeline. The free end of the pressurizing pipeline is connected with the port two of the heat exchanger one. The port one of the heat exchanger one is connected with the port two of the heat exchanger two.

[0006] Further, an electric regulating valve and a temperature sensor are arranged on the pipeline connecting the output end of the hydrogen production system with the port three of the heat exchanger one in sequence along the flow direction of the alkali solution.

[0007] Furthermore, a bypass pipe is connected between port four of heat exchanger one and the inlet of the electric heating device, and an electric regulating valve is installed on the bypass pipe.

[0008] Furthermore, the solar heating device includes a heating tank, which is connected to a solar panel via a heating circuit. The solar panel is electrically connected in sequence to a battery pack and a solar controller, and the battery pack and the solar controller are electrically connected.

[0009] Furthermore, a temperature sensor and an alkali-resistant centrifugal pump are installed on the heating circuit. An electric regulating valve is installed on the pipe connecting the output end of the solar heating device to the input end of the electric heating device. A temperature sensor, a pressure gauge, and an electric regulating valve are installed on the pipe connecting port four of the heat exchanger to the input end of the solar heating device.

[0010] Furthermore, the pipeline connecting the heat exchanger to the mass transfer system is equipped with a pressure gauge, flow meter, throttle valve, pressure reducing valve, and electric regulating valve. Furthermore, temperature sensors are installed on both the input and output pipes of the pressure reducing valve; Furthermore, an electric regulating valve and a temperature sensor are installed between the mass transfer system and the pressurization pipeline.

[0011] Furthermore, a temperature sensor is installed on the pipe connecting port 2 of heat exchanger 2 to port 1 of heat exchanger 1.

[0012] Furthermore, the booster pipeline includes two booster pumps connected in parallel, and both the input and output ends of the two booster pumps are equipped with electric regulating valves.

[0013] Furthermore, a temperature sensor and a pressure gauge are installed on the pipe connecting the solar heating device to the electric heating device.

[0014] Furthermore, a flow meter, a throttle valve, an electric regulating valve, and a temperature sensor are installed on the pipe connecting the outlet end of the electric heating device to the input end of the hydrogen production system.

[0015] Compared with the prior art, the present invention has the following features and beneficial effects: This invention, through the design of a multi-stage heat exchange device consisting of heat exchanger one and heat exchanger two, and a pressure regulating device consisting of a pressure reducing valve and a pressure boosting pipeline, realizes the cascade utilization of system thermal energy, effectively recovers the waste heat of the high-temperature alkaline solution at the outlet of the hydrogen production system, and uses it to preheat the low-temperature alkaline solution returning from the mass transfer system. This significantly reduces the system's dependence on external energy, improves the system's energy utilization efficiency, effectively solves the problem of temperature fluctuation in the electrolyzer in the prior art, and extends the system's service life.

[0016] By integrating a photovoltaic-thermal integrated heat exchange module, the system makes full use of solar energy for alkaline solution heating, significantly reducing the system's demand for traditional electric heating, increasing the contribution rate of renewable energy in the hydrogen production process, and demonstrating good environmental friendliness.

[0017] Through the intelligent temperature control system and data acquisition and automatic control module, real-time monitoring and automatic adjustment of the system's operating status are realized, which improves the system's intelligence and automation level and ensures the system's stable operation.

[0018] By employing a combination of multi-stage pressure reduction regulation and booster pumps, precise cooling and pressure control of the alkali solution were achieved in the secondary heat exchange pipeline, ensuring that the alkali solution returned to the mass transfer system at a suitable temperature and pressure, thereby improving the safety and reliability of the system operation.

[0019] Through systematic thermal integration design and multi-level control strategy, the problems of uneven temperature of various subsystems, high energy consumption and inaccurate temperature control in existing technologies are effectively solved, which greatly improves the overall efficiency and operational stability of the electrolysis hydrogen production system and provides reliable support for the large-scale application of hydrogen energy technology.

[0020] By integrating medium- and low-temperature waste heat with solar energy, precise heating of alkaline solutions can be achieved to meet the temperature requirements of industrial-grade hydrogen production systems. Attached Figure Description

[0021] Fig. 1 This is a schematic diagram of the primary heat exchange pipeline of the present invention; Fig. 2 This is a schematic diagram of the two-stage heat exchange pipeline of the present invention; Fig. 3 This is a schematic diagram of the solar heating device of the present invention; Fig. 4 This is a schematic diagram of the heat exchanger of the present invention.

[0022] The attached diagrams are labeled as follows: 1. Hydrogen production system; 2. Temperature sensor; 3. Flow meter; 4. Electric heating device; 5. Pressure gauge; 6. Solar heating device; 8. Alkali-resistant centrifugal pump; 9. Heat exchanger one; 10. Heat exchanger two; 11. Throttling valve; 12. Pressure reducing valve; 13. Mass transfer system; 14. Booster pump; 15. Cooling water circulation system; 16. Electric regulating valve; 17. Solar panel; 18. Solar controller; 19. Battery pack; 20. Heating tank; 21. Booster pipeline; 22. Bypass pipeline; 23. Heating circuit. Detailed Implementation

[0023] The present invention will now be described in more detail with reference to the embodiments.

[0024] like Figs. 1 to 4As shown, it includes a primary heat exchange pipeline and a secondary heat exchange pipeline. The primary heat exchange pipeline includes a heat exchanger 9, a solar heating device 6, and an electric heating device 4 connected in sequence by pipes. Port 3 of heat exchanger 9 is connected to the output end of hydrogen production system 1, and the output end of electric heating device 4 is connected to the input end of hydrogen production system 1. The secondary heat exchange pipeline includes a heat exchanger 10 and a pressurization pipeline 21. Ports 1 and 3 of heat exchanger 10 are connected to the two ends of cooling water circulation system 15, and port 4 of heat exchanger 10 is connected to the input end of mass transfer system 13. The output end of mass transfer system 13 is connected to pressurization pipeline 21 for pressurizing the alkali solution in the pipeline. The free end of pressurization pipeline 21 is connected to port 2 of heat exchanger 9, and port 1 of heat exchanger 9 is connected to port 2 of heat exchanger 10.

[0025] In this embodiment, heat exchanger 9 is located at the beginning of the main outlet pipeline of hydrogen production system 1. It is mainly responsible for preliminary heat exchange using the high-temperature alkaline solution (70-80℃) generated during the electrolysis process of hydrogen production system 1 and the low-temperature alkaline solution returned after the mass transfer system 13 is replenished with water, and recovering most of the diffused heat.

[0026] Heat exchanger 9 and heat exchanger 10 form a cascade heat exchange structure, realizing the cascade utilization of system thermal energy. They effectively recover the waste heat of the high-temperature alkaline solution at the outlet of hydrogen production system 1, which is used to preheat the low-temperature alkaline solution returned by mass transfer system 13. This significantly reduces the system's dependence on external energy, improves the system's energy utilization efficiency, and completes the synergy and optimization of the entire system in terms of heat, work and other energy grades.

[0027] In this embodiment, the cooling water circulation system 15 is mainly used for the final cooling and pressure regulation of the alkali solution; the secondary heat exchange pipeline can be connected to the external cooling water circulation system 15 to form a closed-loop cooling system; the flow rate of the cooling water can be automatically adjusted according to the feedback information of the temperature sensor 2 to ensure the best heat exchange effect of the heat exchanger 10 and achieve the final cooling of the high temperature and high pressure alkali solution.

[0028] The pipeline connecting the output end of the hydrogen production system 1 to port 3 of heat exchanger 9 is equipped with an electric regulating valve 16 and a temperature sensor 2 arranged sequentially along the direction of alkaline solution flow.

[0029] A bypass pipe 22 is also connected between port four of heat exchanger 9 and the inlet of electric heating device 4. An electric regulating valve 16 is installed on the bypass pipe 22. A flow meter 3, a throttle valve 11, an electric regulating valve 16 and a temperature sensor 2 are arranged sequentially along the direction of alkaline solution flow on the pipe connecting the outlet of electric heating device 4 to the input of hydrogen production system 1.

[0030] In this embodiment, the flow meter 3 is a turbine flow meter, and the heat exchanger 9 is a high-efficiency plate or shell-and-tube heat exchanger with a heat exchange area of ​​10m². By setting high-precision temperature sensors 2 on its inlet and outlet pipes, the state of the alkali solution is monitored in real time, providing a data basis for subsequent intelligent control.

[0031] The electric heating device 4 is installed in the middle and lower section of the main alkali return pipeline of the system. It serves as a guarantee unit for the final temperature control of the system and is used to provide auxiliary heating when the solar thermal integrated heat exchange module cannot meet the heat demand of the system. The power of the electric heating device 4 can be automatically adjusted according to the temperature data fed back by the temperature sensor 2 to ensure the overall thermal balance of the system.

[0032] The electric heating device 4 consists of multiple sets of electric heaters controlled by silicon controlled rectifiers, each with a power of 20kW, for a total power of 60kW.

[0033] The temperature of the alkaline solution after secondary heating and the unheated solution is measured by temperature sensor 2, which triggers the system temperature control unit to regulate the electric heating device 4, automatically adjusting the output power based on the real-time temperature detection signal.

[0034] The solar heating device 6 includes a heating tank 20, which is connected to a solar panel 17 via a heating circuit 23. The solar panel 17 is electrically connected to a battery pack 19 and a solar controller 18 in sequence, and the battery pack 19 and the solar controller 18 are electrically connected.

[0035] The heating circuit 23 is equipped with a temperature sensor 2 and an alkali-resistant centrifugal pump 8. The pipe connecting the output end of the solar heating device 6 to the input end of the electric heating device 4 is equipped with an electric regulating valve 16, a temperature sensor 2, and a pressure gauge 5 arranged sequentially along the alkali flow direction. The pipe connecting the four ports of the heat exchanger 9 to the input end of the solar heating device 6 is equipped with a temperature sensor 2, a pressure gauge 5, and an electric regulating valve 16 arranged sequentially along the alkali flow direction.

[0036] The solar heating device 6 integrates a photovoltaic and solar thermal integrated device. The solar controller 18 is used to automatically adjust the working state of the solar panel 17 according to the ambient light intensity to convert solar energy into electrical energy. When the ambient light intensity is high, the solar controller 18 generates electricity and stores the electrical energy in the battery pack 19. When the ambient light intensity is low, the solar controller 18 stops generating electricity.

[0037] The heating tank 20 has a multi-layer serpentine coil structure with a heat exchange area of ​​10m². The material is usually 316L stainless steel or other alkali-resistant alloys to increase the heat exchange area and adapt to corrosive media. The solar heating device 6 can effectively use solar energy to supplement the heating of alkaline solution, significantly reducing the system's dependence on traditional electric heating.

[0038] After the solar panel 17 generates electricity, the electrical energy is distributed by the solar controller 18: it is preferentially used to drive the electric heating element in the heating tank 20 to directly heat the alkaline solution in the tank; the excess electrical energy is stored in the battery pack 19 and released when there is insufficient sunlight to continue to heat the alkaline solution.

[0039] The alkali-resistant centrifugal pump 8 is used to pump the medium in the heating tank 20. The medium is heated by the heating circuit 23 and circulates in the solar heating device 6 to heat the alkali solution.

[0040] The pipeline connecting heat exchanger 2 10 to mass transfer system 13 is equipped with a pressure gauge 5, a flow meter 3, a throttle valve 11, a pressure reducing valve 12, and an electric regulating valve 16 arranged sequentially along the direction of alkali flow; temperature sensors 2 are installed on both the input and output pipes of pressure reducing valve 12; an electric regulating valve 16 and temperature sensors 2 are installed between mass transfer system 13 and pressurization pipeline 21.

[0041] By setting up multi-stage pressure reduction regulation and heat exchanger 210, the state of the alkali solution is jointly regulated to make it conform to the inlet parameters of the mass transfer system 13.

[0042] A temperature sensor 2 is installed on the pipe connecting port 2 of heat exchanger 2 10 to port 1 of heat exchanger 1 9.

[0043] The booster pipeline 21 includes two booster pumps 14 connected in parallel, and both the input and output ends of the two booster pumps 14 are equipped with electric regulating valves 16.

[0044] A temperature sensor 2 and a pressure gauge 5 are installed on the pipe connecting the solar heating device 6 to the electric heating device 4.

[0045] In the pressurization pipeline 21, the atmospheric pressure alkaline solution through the mass transfer system 13 passes through the pressurization pump 14, which is an alkali-resistant pressurization pump, to provide power and pressurize the alkaline solution to reach the required 0.6 MPa for the reaction, and then enters the primary heat exchange pipeline for heat exchange.

[0046] The combination of multi-stage pressure reduction regulation and booster pump 14 enables precise control of the cooling and pressure of the alkali solution in the secondary heat exchange pipeline. Pressure reducing valve 12 and throttle valve 11 work together to achieve precise control of the system pressure, while booster pump 14 provides the necessary power for the alkali solution to return to the mass transfer system 13, ensuring that the alkali solution returns to the mass transfer system 13 at a suitable temperature and pressure, thereby improving the safety and reliability of the system operation.

[0047] A temperature sensor 2 is installed on the pipe between heat exchanger 9 and heat exchanger 10.

[0048] Temperature sensor 2 and electric regulating valve 16, which are installed on the pipeline, are connected to PLC controller to form an intelligent temperature control system. Temperature sensor 2 collects the fluid temperature at each stage in real time, and the signal is transmitted and uploaded to the control system. Electric regulating valve 16 can realize multi-level opening adjustment according to control instructions. The system automatically switches the operating mode according to the preset strategy to realize the rational distribution of heat energy and the comprehensive energy saving of the system. PLC controller is used to receive the signal from temperature sensor 2 and transmit instructions to electric regulating valve 16.

[0049] The PLC controller, based on PID or fuzzy control algorithms, dynamically adjusts the power of the electric heater, the speed of the pump, and the opening of the valves to achieve closed-loop control of the system's thermal parameters, thereby significantly improving the system's automation level, temperature control accuracy, and overall operating efficiency.

[0050] The working principle of this invention is as follows: The high-temperature alkaline solution in the hydrogen production system 1 is transported to heat exchanger 9 through a pipeline. Heat exchanger 9 performs preliminary heat exchange on the high-temperature alkaline solution, recovering most of the diffused heat. After heat exchange, the alkaline solution is transported to heat exchanger 10 to achieve final cooling. The high-pressure alkaline solution is reduced to atmospheric pressure through pressure reducing valve 12 to ensure that the system pressure is within the range of 0.1 MPa. The alkaline solution after final cooling is transported to mass transfer system 13.

[0051] The alkaline solution after passing through the mass transfer system 13 is pressurized by the booster pump 14 to reach the required 0.6 MPa, and enters the primary heat exchange pipeline 30 as a cold source. The alkaline solution is transported to the heat exchanger 9 to exchange heat with the high-temperature alkaline solution from the hydrogen production system 1 to complete the heat recovery. The preheated alkaline solution after heat exchange is transported to the solar heating device 6 for secondary heating. The alkaline solution that has undergone secondary heating but has not reached the required heat of the system is transported to the electric heating device 4 for tertiary heating. The high-temperature alkaline solution after tertiary heating is transported to the hydrogen production system 1.

[0052] In the description of this invention, it should be noted that the terms "inner", "outer", "upper", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0053] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0054] Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

Claims

1. A system for optimizing the use of thermal energy based on a hydrogen production system by direct electrolysis of seawater, characterized in that it comprises: The first heat exchange pipeline and the second heat exchange pipeline are connected in series. The first heat exchange pipeline comprises a heat exchanger one (9), a solar heating device (6) and an electric heating device (4) connected in series through pipelines, the port three of the heat exchanger one (9) is connected to the output end of the hydrogen production system (1), and the output end of the electric heating device (4) is connected to the input end of the hydrogen production system (1). The second heat exchange pipeline comprises a heat exchanger two (10) and a booster pipeline (21), the port one and the port three of the heat exchanger two (10) are connected to the two ends of the cooling water circulation system (15) respectively, the port four of the heat exchanger two (10) is connected to the input end of the mass transfer system (13), and the output end of the mass transfer system (13) is connected to the booster pipeline (21) for boosting the lye in the pipeline. The free end of the booster pipeline (21) is connected to the port two of the heat exchanger one (9), and the port one of the heat exchanger one (9) is connected to the port two of the heat exchanger two (10).

2. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The pipeline, on which the output end of the hydrogen production system (1) is connected to the port three of the heat exchanger one (9), is provided with an electric regulating valve (16) and a temperature sensor (2) arranged in the lye flow direction in sequence.

3. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The port four of the heat exchanger one (9) and the inlet end of the electric heating device (4) are further connected by a bypass pipeline (22), and the bypass pipeline (22) is provided with an electric regulating valve (16).

4. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 3, characterized in that: The solar heating device (6) comprises a heating tank (20), the heating tank (20) is connected with a solar panel (17) through a heating loop (23), the solar panel (17) is electrically connected with a battery pack (19) and a solar controller (18) in sequence, and the battery pack (19) and the solar controller (18) are electrically connected.

5. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 4, characterized in that: The heating loop (23) is provided with a temperature sensor (2) and an alkali-resistant centrifugal pump (8), the pipeline, on which the output end of the solar heating device (6) is connected to the input end of the electric heating device (4), is provided with an electric regulating valve (16), and the pipeline, on which the port four of the heat exchanger one (9) is connected to the input end of the solar heating device (6), is provided with a temperature sensor (2), a pressure gauge (5) and an electric regulating valve (16).

6. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The pipeline, on which the heat exchanger two (10) is connected to the mass transfer system (13), is provided with a pressure gauge (5), a flowmeter (3), a throttle valve (11), a pressure reducing valve (12) and an electric regulating valve (16). The input end and the output end of the pressure reducing valve (12) are both provided with a temperature sensor (2). An electric regulating valve (16) and a temperature sensor (2) are arranged between the mass transfer system (13) and the booster pipeline (21).

7. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The pipeline between the port two of the heat exchanger two (10) and the port one of the heat exchanger one (9) is provided with a temperature sensor (2).

8. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The booster pipeline (21) comprises two booster pumps (14) arranged in parallel, and the input end and the output end of each of the two booster pumps (14) are provided with an electric regulating valve (16).

9. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The pipeline, on which the solar heating device (6) is connected to the electric heating device (4), is provided with a temperature sensor (2) and a pressure gauge (5).

10. The system for optimizing the utilization of thermal energy based on seawater direct electrolysis hydrogen production system according to claim 1, characterized in that: The pipeline, on which the outlet end of the electric heating device (4) is connected to the input end of the hydrogen production system (1), is provided with a flowmeter (3), a throttle valve (11), an electric regulating valve (16) and a temperature sensor (2).

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